The present invention relates to a portable machine tool and particularly to a portable machine tool for translating a milling cutter in three dimensions without restriction in travel crossways of the machine tool.
Ram type machine tools are characterized by triaxial positioning of a milling cutter. However, travel of the machining head can be somewhat restricted in one or more dimensions. A ram type milling machine conventionally comprises a longitudinal bed along which a carriage travels and a ram mounted on the carriage by means of a cross slide. A vertically movable machining head is disposed at one end of the ram for positioning in X, Y and Z directions in order to machine a desired surface. Although the ram can be cantilevered outwardly a substantial distance from the carriage, nevertheless the machining head is incapable of machining a surface completely across the machine tool bed from one side thereof to the other since the ram is mounted for transverse movement on the carriage and also because the machining head usually depends from one end of the ram. Therefore, machining is normally carried out entirely on one side of the longitudinal bed. This limitation can be of disadvantage, especially in the case of portable machine tools where it is desirable to mount the machine bed on one of two parallel surfaces for the purpose of machining the opposite parallel surface. One example relates to parallel press platens wherein a limited space is available for mounting the machine tool bed on one platen for machining the opposite platen.